Dryland regions cover about 41% of Earth's land surface and are home to more than two billion people, yet their role in global microplastic pollution has received relatively little scientific attention. A new review suggests that open dumpsites in these regions may act not simply as places where plastic waste accumulates, but as active environments that accelerate its transformation into persistent and potentially more hazardous microplastics.
Published in New Contaminants, the review analyzed 87 peer reviewed studies published between 2016 and 2026. The researchers examined how environmental conditions unique to drylands influence the formation, weathering, transport and ecological effects of microplastics.
"Our review shows that dryland dumpsites should not be viewed as passive storage sites for plastic waste," said corresponding author Abdulrazaq Izuafa of the Federal University Birnin Kebbi, Nigeria. "The combination of intense sunlight, large temperature changes, wind abrasion and limited moisture can continuously break plastics into smaller particles while preventing their complete biological degradation."
Ultraviolet radiation is one of the most important drivers. Strong sunlight promotes photooxidation, weakening polymer chains and making plastics brittle. Large day and night temperature changes create additional cracks, while windblown sand and dust physically abrade already weakened surfaces. Because low moisture suppresses microbial activity, fragmentation can occur much faster than complete decomposition.
The review found evidence that plastic weathering under dryland ultraviolet conditions can proceed substantially faster than under temperate conditions. Thin plastic films may be particularly vulnerable because their large surface area relative to their mass allows greater exposure to sunlight and oxidants.
Open burning adds another layer of concern. Instead of completely eliminating plastic waste, uncontrolled burning can produce charred, fused and chemically altered plastic particles. These materials may carry polycyclic aromatic hydrocarbons and other combustion related contaminants and can be dispersed beyond dumpsites through airborne particles.
Weathering also changes how microplastics interact with other pollutants. As their surfaces become rougher, more porous and chemically reactive, they can bind heavy metals and organic contaminants more effectively. The review reports that aging has been associated with increases in metal adsorption of 2.8 to 11.4 times and increases in organic pollutant partitioning of 1.9 to 6.7 times.
Microplastics can then move far beyond the waste site. Wind transports lightweight films and fibers through the atmosphere, flash floods redistribute particles across landscapes, and rainfall can move smaller particles downward through soils. These pathways may carry microplastics and their associated contaminants toward agricultural land, surface waters and groundwater.
The researchers also highlight emerging biological risks. Microplastic surfaces can host distinct microbial communities known as the plastisphere. Evidence reviewed in the study indicates that antimicrobial resistance genes can be strongly enriched in these communities compared with surrounding soil, raising concerns about dumpsites as potential reservoirs for resistance.
Despite growing evidence, major uncertainties remain. Only about 9% of the studies reviewed quantified particles smaller than one micrometer, suggesting that nanoplastic pollution may be substantially underestimated.
"Better monitoring is essential if we want to understand the true scale of the problem and design effective interventions," Izuafa said. "Standardized analytical methods, long term field observations and models that connect wind, runoff and soil transport will be especially important."
The authors call for integrated dryland observatories combining field measurements, advanced imaging, multiomics approaches and remote sensing technologies. Such efforts could provide the evidence needed to improve waste management, environmental risk assessment and policies for communities living near open dumpsites.
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Journal reference: Izuafa A, Edoamodu CE, Musa J, Ozue EC, Nathaniel J. 2026. Microplastics' formation and fate in dryland dumpsites: Environmental drivers, transformation pathways, and ecotoxicological implications. New Contaminants 2: e023 doi: 10.48130/newcontam-0026-0020
https://www.maxapress.com/article/doi/10.48130/newcontam-0026-0020
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About the Journal:
New Contaminants (e-ISSN 3069-7603) is an open-access journal focusing on research related to emerging pollutants and their remediation.
